The MIMO Test Bed
Real-time MIMO-OFDM testbed is a research initiative of the Iqra
University sponsored by ICT R&D Fund. The aim is to develop a
testbed that can help in the design, analysis and rapid prototyping of
future MIMO-OFDM systems.
With all their advantages MIMO-OFDM systems,
when compared with its single antenna counterparts, are not only more
sensitive to channel estimation and synchronization errors but also
require a lot more computational power and implementation
effort. MIMO systems demand perfect
estimate of the channel matrix at
the receiver to successfully decode the
received signal.
Channel estimation is a challenging task because in MIMO systems different signals are transmitted from transmit antennas and received signal at each antenna is the superposition of all the transmitted signals. Sensitivity to synchronization errors comes from the fact that a MIMO-OFDM system requires simultaneous transmission and reception of parallel spatial signal streams from its antennas. A slight misalignment caused by a timing synchronization error can lead to serious degradation in the performance. Optimum Maximum Likelihood (ML) MIMO decoder can become almost impossible to implement when constellation size and number of antennas approaches a certain threshold.
There has been a significant research to resolve these issues over the last few years and various solutions have been proposed but practical MIMO-OFDM system design still pose a challenge for communication system designers. more...